Planar, thin-layered chiral plasmonic superstructures with complex two-dimensional (2D) patterns, namely, double-layered binary stars (bi-stars) and pinwheels, were realized through DNA programmable 2D supramolecular self-assembly of gold nanorods (AuNRs). The chirality of the chiral superstructures was defined by a finite number of AuNR pairs as enantiomeric motifs, and their sizes (∼240 nm) were precisely defined by the underlying DNA template. These planar, thin-layered chiral nanoparticle superstructures exhibited prescribed shapes and sizes at the dried state on the substrate surface and are characteristic of giant anisotropy of chiroptical responses, with enhanced g-factors from the axial incident excitation as compared to the in-plane excitation. This work will inspire possibilities for the construction of 2D chiral materials, for example, chiral metasurfaces, for the on-chip manipulation of chiral light-matter interactions via programmable self-assembly of nanoparticles.
Keywords: DNA self-assembly; chiral plasmonics; g-factor; gold nanorods; thin-layered chiral superstructure.